This invention relates generally to transponders and particularly relates to a redundancy switching system therefor.
Transponders of the type used particularly in spacecraft usually require a considerable amount of redundancy to provide for failure of one or more of the key elements of the system. In the past, it has been conventional practice to provide redundancy by using one standby unit for each active unit. Simple switches may be used to replace a failed unit and this has shown to provide a moderate increase in reliability.
Many transponders consist of transmission channels utilizing many identical units such, for example, as traveling wave tube amplifiers. In that case, providing one standby amplifier for each active amplifier significantly increases the weight without optimizing reliability.
In a switch system, for example, the transmitters and antennas could be interconnected by a matrix which may utilize, for example, crossbar switches, or diodes and the like to switch in a standby unit for a failed unit. Generally, such systems cannot be used for microwaves. The required switching has frequently resulted in mechanically complex configurations providing high signal loss.
It is, therefore, an object of the present invention to provide a redundancy switching system for transponders of the type having equal elements such as amplifiers which can be readily realized and where the weight and size are linearly proportional to the number of elements.
A further object of the present invention is to provide a redundancy switching system of the type discussed where the switches themselves are redundant.
Another object of the present invention is to provide a redundancy switching system of the type referred to which requires no more than two mechanical transfer switches for each amplifier or element.